Sell me a thtory

There's lanthanum and osmium and astatine and radium, And gold and protactinium and indium and gallium, And iodine and thorium...

Aah, thorium…the nuclear panacea. Or, is it?

CERN, home of the Large Hadron Collider (LHC) that last year found evidence of the so-called "God particle" that earned Peter Higgs this year's Nobel prize in physics (as predicted on this blog! Howay, the lad…yes he was born in Newcastle not Scotland, not Bristol), might think so. The organization Conseil Europeen pour la Recherche Nucleaire is to host an international conference to discuss the potential of thorium-fired nuclear power. Thorium holds the promise, the conference blurb suggests, of not only providing a cleaner nuclear option but also a safe way to dispose of nuclear waste. It sounds like alchemy, but...

Of course, CERN and others pioneered research into thorium in the 1990s instigated by another Nobel laureate, Carlo Rubbia. Thorium is a silvery white metal four times more abundant in the Earth's crust than the publicly more familiar uranium on which current nuclear power is built. According to its Wikipedia entry, thorium generates radon-220 as one of its decay products, while radium and actinium are secondary decay products. The most abundant isotope of the element is thorium-232, which undergoes alpha decay with a half-life of about 14 billion years, its abundance means no enrichment is needed. Its other isotopes exist only as short-lived intermediates in the decay chains of heavier elements.

Its abundance fact and its potential as both fuel and the means to reduce nuclear waste lifetimes have kept it high on the agenda among those in the know. Several nations have already embarked on plans to develop the next generation of power plant that uses thorium (Th) instead of uranium (U). China and India are actively supporting several initiatives in this direction with important resources, and the United States, Russia, Europe, Japan, South Korea, and Norway are also evaluating this technology.

"Energy is a major concern for society and I’m sure that this conference will show once again how fundamental research can help to address such an important challenge," Rolf Heuer CERN Director General reportedly said, according to CERN's press release on the conference.

Thorium itself is a "fertile" nuclear material, it is not itself fissile but can be converted into an active form - Th-233- by exposure to an appropriate chipping or "spallating" neutron source. Nuclear reactors using some thorium date back to the 1950s. However, it is only in recent years that its possible advantages over uranium have come to the fore as serious environmental concerns about conventional nuclear power, the mining of uranium ore, its processing, the long-lived waste products have come to the fore. Some pundits have estimated that we have access to sufficient thorium to power the globe for several thousand years, even if we all continue to have to charge our smart phones daily...

Among the pioneers in thorium reactor research is a team at the University of Huddersfield led by Bob Cywinski and Roger Barlow, which points out that thorium is "low waste", does not include plutonium in its fuel cycle, offers 100 times the energy density of uranium, is intrinsically proliferation resistant, fail-safe because a reactor must be kept active, no runaway chain reaction is possible. They are developing the Accelerator Driven Subcritical Reactor, or ADSR, such an installation could be hooked up to the UK power grid by 2025 and supply a large proportion of our energy needs by then. Cywinski and Barlow have founded ThorEA, a UK academic group investigating thorium power, with colleagues at the University of Cambridge and University of Manchester.

However, there are observers who point out that commercially viable thorium reactors are a long way off and even if we see 2025 as the advent of this form of nuclear power, we have more than a decade of smart phone charging...and all those other power demands...to fill. Global power demands are only going to increase as the developing world develops and our fascination with electrical systems does not dwindle. The stopgap is not likely to be wind or solar despite the grandiose schemes of their proponents, subsidized by the "low-carbon" tab that will one day have to be paid off. Nuclear could be the option and sustaining the hope of thorium reactors could keep nuclear ticking over longer. But, it is more likely that we will simply carry on burning fossil fuels to generate electricity as we have done for decades. We will put up with the consequences or more likely suffer their seriously deleterious effects in climate change. Thorium may well be a power panacea, but enthusiastic conference delegates aside it seems more likely to remain a pipedream for as long as the carbon industry wants it to remain so.

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